"Paul Ryan works in Washington, but his beliefs remain firmly rooted in Janesville, Wis.," Romney said, a reference to Ryan's home in the critical swing state.

With a retired battleship - the USS Wisconsin- as their backdrop, Romney and Ryan shook hands and embraced after Romney mistakenly introduced the congressman as "the next president of the United States" instead of vice president. Romney then corrected himself as Ryan stepped to the microphones.

Two hours before the event, the Romney campaign announced the pick through its "Mitt's VP" smartphone app early Saturday morning. The Associated Press, citing unnamed campaign aides, said Romney actually made his decision Aug. 1, but kept it quiet for 10 days.

Ryan, 42, is best known as the chairman of the House Budget Committee and author of a dramatic plan to overhaul Medicare, the government-run health insurance program for senior citizens.

And while Romney said Ryan is well-respected, even by Democrats, and doesn't "demonize" his opponents, Ryan still hit partisan notes in his speech.

"Following four years of failed leadership, the hopes of our country, which have inspired the world, are growing dim. They need someone to revive them. Governor Romney is the man for this moment. And he and I share one commitment: we will restore the dreams and greatness of this country," Ryan said. "President Obama, and too many like him in Washington, have refused to make difficult decisions because they are more worried about their next election than they are about the next generation"

Ryan also touched on a favorite GOP campaign theme. "I'm proud to stand with a man who understands what it takes to foster job creation in our economy, someone who knows from experience, that if you have a small business - you did build that," he said, a line followed by a loud cheer from the crowd.

The line echoed a theme from Romney ads and speeches attacking Obama for saying about business owners: "You didn't build that."

Democrats say Obama was taken out of context - he was discussing the infrastructure such as roads and technology that support those businesses.

Ryan, who began his work in politics when he was 22 years old, cited his history in Washington as a strength.

"I believe that my record of getting things done in Congress will be a very helpful complement to Governor Romney's executive and private sector success outside of Washington. I have worked closely with Republicans as well as Democrats to advance an agenda of economic growth, fiscal discipline and job creation."

With Ryan as his running mate, Romney appears ready to have a national conversation about federal spending and the growth of entitlements with one of the GOP's leading budget authorities at his side.

Ryan, a House member since 1999, has proposed to dramatically change both Medicare and Medicaid, the programs that have been a hallmark of the nation's compact to provide health care to senior citizens and the poor

In March, Ryan led House Republicans in releasing a budget plan that would repeal Obama's health care law, cut billions in spending and overhaul the federal tax code in order to reduce - but not eliminate - the federal deficit over the next 10 years.

Ryan said at the time that the proposal was philosophically rooted in reducing Americans' reliance on the federal government. "It's about turning our system that has become a dependent culture into an upward mobile society, getting people back onto lives of self-sufficiency," he said.

Ryan's budget plan has been widely criticized by Obama and his fellow Democrats, who contend it would "end Medicare as we know it." In an April speech, Obama called it "thinly veiled social Darwinism."

The Ryan plan would restructure Medicare for future beneficiaries to allow those 55 and younger to opt out of the system and purchase private insurance with a federal subsidy.

Paul Branum, 54, a government comptroller from Virginia Beach, was one of thousands of people gathered here to cheer the two men.

"I think it's a good pick," Branum said of Ryan. "He's got the budget background that we are going to need to go forward for the next four years. He clearly is better at policy then the other people that were (considered)."

Branum said Ryan's experience inside Congress would "absolutely" help the ticket, despite the anti-Washington sentiment.

"I think he knows how Congress works, he's been there for a while and you are going to need that to work policy through Congress," he said.

Romney had announced that Saturday's Norfolk event would kick off a four-day bus tour of swing states that will also include North Carolina, Florida and Ohio. A campaign adviser told reporters Ryan will join the bus trip through Virginia and North Carolina.